Flowmeter



May 5, 1953 E. R. ATKlNs, JR

FLOWMETER Filed Oct. 13. 1949 c1 nja n n'q 47m/Mix May 5, 1953 E. R. ATKlNs, JR 2,637,206

FLowMETER Filed 00T'. 15, 1949 2 SHEETS-SHEET 2 Patented May 5, 1953 UNITED STATES PATENT OFFICE FLOWMETER Earle R. Atkins, Jr., La Habra, Calif., assigner to Union Oil Company of California, Los Angeles, Calif., a corporation of California Application October 13, 1949, Serial No. 121,166

(Cl. "J3-455) 3 Claims. l

This invention relates generally to apparatus for measuring fluid flow, and more particularly to apparatus for measuring the flow of iiuids, such as oil, within an oil well bore.

It is an object of this invention to impress an electrostatic charge upon an Iincrement of flowing fluid and to time the arrival of the charged portion of the fluid at some particular downstream point by detecting the residual charge of the increment of fluid.

It is another object of this invention to measure the rate of -cw in a ilowing fluid by periodically impressing an electrostatic charge upon increments of the owing stream and detecting the arrivals of the charged increments at a downstream location.

Attached Figure l presents one embodiment of the invention wherein a owmeter unit is lowered into a well bore lled with fluid to determine the inuent fluid rate.

Attached Figure 2 presents a photographic record of the data obtained with embodiment of the invention shown in Figure 1 from which record the fluid ow may be calculated. v

Figure 3 presents a fragmentary cross section of the flowmeter taken along line 3-3 of Figure 1, showing the detector electrodes and their association with the electrical elements of Figure l.

Figure 4l is a diagrammatic representation showing an alternative arrangement for the flowmeter units.

Figure r5 shows another alternative arrangement of ilowmeter units employing an oscilloscope as the current detecting mechanism.

Briefly this invention relates to a new method for the determination of the rate of fluid flow wherein least a part of the flowing stream to be measured is passed between two charging electrodes which are connected to a source of electric potential thereby charging an increment of theowing fluid with an electrostatic charge. As a result of the normal flow ofthe fluid the charged increment is transported downstreanm wardly whence it passes between two detecting electrodes which are tted with suitable means for determining the arrival of the charged increment `by detecting its residual electrostatic charge. Suitable means are also provided for determining the lapsed time interval between the charging and detecting steps, which interval determines the velocity of the lluid between the two sets of electrodes. The new rate of the fluid is then determined from calibrations of the equipment or calculations from the fluid velocity.

In one embodiment of the invention the flowmeter is used to determine the vrate of influent into a well bore such as an oil well bore. In a particular modification of the well bore flowmeter a iiowmeter unit is suspended by a supporting cable and lowered into the liquid lled bore hole. The flowmeter unit itself comprises two parts viz. an upper enclosed sealed section and a lower non-sealed section open to the Huid iiow. The sealed section contains a means for generating a high electrical potential, a means for pulsing such electrical potential whereby periodic pulses of relatively short duration and of low periodic frequency are obtained and means for recording the deflections of a galvanometer such as by recording the relative times of such deflections by the marking of a moving strip of photographic lm with a movable illuminating device. The lower non-sealed section comprises a tubular section having a lower open end and suitable holes near the top. A suitable intervening passageway permits the relatively free ingress of fluid in the bottom and egress of fluid through the holes at the top. Near the bottom of the non-sealed section there are positioned two charging electrodes, viz. an inner `and an outer cylindrical shaped charging electrode. The outer is supported from the tubular section and the inner is supported by an inner electrode support coaxial to the tubular section. A fluid passageway passes through the annular space between the electrodes. A short distance above the charging electrode and below the iiuid egress holes are two detecting electrodes which cor respond structurally tothe charging electrodes.

At such time as the potential is applied to the electrodes from the high potential generator or source the increment of the flowing stream passing through the charging electrode, annular space at that instant acquires an electrostatic charge. After a momentary charging period the timer shuts 01T the current flow. The normal flow of the lluid causes the charged portion of the liquid to pass upwardly through the chamber whence it passes between the two detector electrodes. The arrival of the fluid carrying the electrostatic charge within the annular space of the detecting electrodes causes a charge to be set up between the two detecting electrodes which, when conveyed through suitable conductors to the recording galvanometer, causes a deilection. The recording galvanometer record nlm is marked at the instant the charge is applied to the charging electrodes and when the charged liquid is detected in the detector electrode as well as at some denite time interval such as at the end of each second. 'Ihe lapsed time interval between the charging and detecting steps is thusly determined. This lapsed time interval is the fluid transit time to move the liquid the average distance between the two sets of electrodes. The fluid velocity determined by such time interval and distance also determines the fluid flow rate in a given size pipe for a particular instrument.

Referring now more particularly to attached Figures l and 3, bore hole I is completed through various miscellaneous formations I2 into oil bearing formation I3. Oil flowing from oil bearing form-ation I3 illls bore hole the upper liquid level being indicated at |4 and such flowing oil -is removed from the bore hole by suitable means not shown. Flowmeter unit I5 is suspended in the proximity of the oil bearing formation I3 by means of supporting cable I6 attached to and Wound on winding drum Il. Winding drum |'I is also fitted with suitable depth of instrument indicating means not shown. Flowmeter unit I5 is composed of sealed, upper, liquid-tight section 40 which encloses high voltage source 43, high voltage source timer 42 and recording galvanometer 4|.

High voltage direct current source 43 is any suitable source. In one form it comprises a means for interrupting a direct current source from batteries to produce an interrupted current which is then applied to a suitable transformer to produce high voltage alternating current. The alternating current is then rectified and .filtered by means of a illter condenser to produce the desired high voltage. High voltage timer 42 comprises any suitable, mechanical or electrical means for pulsing the flow of the high voltage current from high voltage source 43 to produce momentary direct current ilows of short duration, each of which flows is considerably spaced from the preceding and succeeding current flows. Timer 42 is connected to high voltage source 43 by means of conductors 22 and 23 respectively.

The recording galvanometer 4| shown in Figures l and 3 comprises any suitable type for recording the deflections of the galvanometer such that the time interval between such dellections can be determined. In one embodiment such record may be produced upon a strip of photographic film, as shown in Figure 2, which is caused to unwind slowly past one and preferably two light sources. The one light source is modulated by any suitable timing device such that time marks are indicated upon the illm at periodic intervals such as the end of each second, at the end of each minute, etc. The same or preferably a second light source is modulated bv any suitable method to indicate the instant which timer 42 causes a high voltage current to flow from high voltage source 43 and also to indicate the deflection of the galvanometer resulting from the charging of the detector electrodes described hereinafter.

The lower section of ilowmeter unit I5 consists of a tubular section 3|] coaxiallv attached to sealed section 40. The lower section is open at its lower end tn permit the ingress of fluid and has two holes 36 and 31 at its upper end which permit the egress of iluid. Coaxially mounted within the tubular section 30 is sealed electrode support 28, the upper end of which connects with the inner chamber of sealed unit and is supported therefrom. A charging electrode section is contained in the lower open section and consists of cylindrical outer charging electrode 32 mounted coaxially within the tubular section 3B, and inner charging electrode 34 mounted on electrode support 28 and coaxially within the outer cylindrical electrode 32. The annular space between the outer and inner charging electrodes, 32 and 34 respectively, provides a path for the upwardly flowing fluid. Above the charging electrode at a suitable distance therefrom, there are mounted two detect ing electrodes, outer detecting electrode 3| and inner detecting electrode 33 respectively, which electrodes correspond structurally to the previously described charging electrode. In the preferred modification both the charging and the detecting electrodes are covered with a thin film of an electrically non-conductive material such as a polymerized methyl acrylate. This insulation is indicated at 3| a and 33a in Figure 3. The illm, or other such covering, insulates the electrodes from actual physical contact with the flowing liquid and increases the electrical resistance between the respective pairs of electrodes.

The outer charging electrode is connected with high Voltage source 43 by means of line 24 which passes through the wall of the sealed section at sealed insulator 26. The inner charging electrode is connected to the outer terminal of the high voltage charging source 43 through lines 29 and 25. Outer detecting electrode 3| is connected to one terminal of recording galvanometer 4| by line 20 which passes into the sealed section through sealed insulator 21. Inner detecting electrode 33 is connected by means of lines 29 and 2| to the other terminal of the recording galvanometer 4|.

Timer 42 is connected to high potential source 43 through lines 22 and 23 and causes the high potential from source 43 to be momentarily connected with the charging electrodes and thereafter disconnected until the time of the next periodic charging cycle.

Timer 42 is also connected to recording galvanometer 4| bymeans of leads 44 and 45 respectively. Whenever the charging potential is applied to the charging electrodes by the action of the timer 42, the timer also sends a small current to cause the deflection of the galvanometer at the same instant to mark the charging time upon the lm record.

In the operation of the equipment the flowmeter unit I5 is positioned at some fixed point within bore hole I I where the flow is to be measured. A part of the upwardly flowing fluid flows through open end 35 of tubular unit through the annular space between the inner and outer charging electrodes 32 and 34 respectively. 'Timer 42 causes a momentary connection of high voltage source 43 with the charging electrodes at some time during the flow whereby a difference of potential is set up between the inner and outer electrodes, 32 and 34 respectively, thereby imparting an electrostatic charge to the increment of flowing fluid in the annular space therebetween. At the same instant the timer 42 vpasses a small current to the recording galvanometer to mark the record at the time of the charging of the increments of the uid. The normal flow of fluid causes the transfer of the charged increment of fluid upwardly through the tube whence it enters the detecting electrode section. Entry of the charged fluid in the annular space between inner and outer detecting electrodes, 3| and 33 respectively, causes a charge to be imparted to the electrodes which is conveyed to recording galvanometer 4| thereby yEine 56 is Aproduced :by :the timing blight -ywith traces itil, :Strand iS-marking a-.unitftime interval Hsucheasxminutes, seconds, tenthsof'secondsaor :other `rsuch :time :measure :Line vtil represents Lthe.galvanometerftrace with majoixpealrs 1:52 z and .5.4 :trepresenting Asuccessive Lcharging .times .rand

minor peaks :c3 V,and '155 `representing the zar-'rivals A.of l.char-ged lud laetweentthe detector electrodes. JThe lapsed time :interval ibetween -peaks L52 vand ..53 nis i the time ffor :the .ilu-id kto #travel .from the Icharging electrode .to lthe detecting electrode,

.which for-z aigivenspacing: of the electrodes .fixes the velocity of -jthe ...fluid -in `the-phamber. Such velocity is then related by empirical calibration to ,thetveiocity ofztheifiuid'generallv. from which data the rate of flow can be calculated.

AExample A particular well is suspected oihaving a leaky casing -Sat point .A above fthe producing Izone.

The .casing has van `inner.dianleter oi :about A6 inches and 120 .barrels/day o'f'crude oil areibeing :removed fromthe Ywell at fthe earth :surface 'A ifiowmeter .of ythe .type vdescribed herein fis placed in fthe V-well bore-abovepoint Aan'dfthe oil iiowingitherethrough is charged periodically f .with a v tolztage` of 300 vol-ts for :about =`0f1001 =sec. The charged oil is detected'byithefdetecting `electrode on the averageaof about.2.1fseccnds later. The vertical distance from the midpoint of the charging electrode to themidpoint of the detectingelectrode'is1.0-inch. Whererthe oilii-ows at the rate of l inch per 2.1 seconds in a 6 inch cas ing the flow rate is 126 barrels/day. Thus the instruments blocking a part of the oil flow causes a velocity increase of the oil flowing through the instrument by about 4%.

The instrument is then lowered to a point between point A and the producing zone. Using the same charging potential and charging time, the charged oil is detected about 1.9 seconds after the charging potential is applied. The oil iiow rate at this point is Thus since 133 lit/1D.` are fiowing from the producing zone and only 120 B./D. are being produced at the earth surface, about 13 B./D. are being lost from the casing near point A.

The foregoing description of this invention has been specically directed to the case where the entire power supply, timing unit, and recording equipment are lowered in a singie unit in conjunction with the charging and detecting electrodes. Although the foregoing modification is generally preferable, it is apparent however that it is not the' only one which may be employed. For example, as indicated in Figure Li, the power supply and timer 42 could be located at the surface and the charging current transmitted down a conductor cable to the charging electrodes 32 and IM. Instead of recording galvanometer deflections at the location of the lowmeter, the detector electrodes 3| and 33 in series with a xed X120: l33 BJD.

capacitance 6D could be applied as an inout to a- Lofton-White type D.C. amplifier Sl. The outi6 ''nutrofrthezampliiierrcould.bepassedethroughsuit t-ablegconductorleadsitoe:theiearthiisurface' and emv played :to @operate:Marecording7 vo1tmeterz6'3. :In

"this flatter Nease ithe ,'tcharging iptime gand suitable @time rmark-s would .he :rnarked .upon .the yrecord analogousito the :oasezrof 'ithephotographic lm. The iieterminationxof 'uildi flow from thexrecord is eexactlyganalogoustto that previously described Aiorgthesgalvanoitfretertrecord.

yWhilefthe foregoing; applications :of Vthis invention have `ibzeenispecically:directed` to :the measurement of: oil; flow =.within.-a :well bore,V it is V'ap- Lparent 'zthat #..thei invention :may .be similarly employed: to measureeoihnow Within va pipasuch'as .iaqaipejinejiby:merely placing; afpair `of :charging electrodes and a pair;ofdetectingelectrodes within @1afsnitablyrinsulatedi sectionof `vpipe. The in- '.wention :imay Libe. similarly `:employed '5to 1 measure flow fof .ffiui'ds .other than :oil such fas 'those .whichhavellowzfdielectric.constantsgsuch'asthose which 5 have dielectric .constants of less :than T20 yand.oprei-.".erably lessthan' 1.5. 'Theilowiof liquids ,wh-ichhave.higherdielectricfconstantsfand which haverlow.'conductivityrcanfalso .be measured.

11n certain: casestherecording lof the galvanomeetende'ections, is dini-cult; or.` even impossible such as #where .the .nu-id ifiow gis vextreme'ly rapid :or .wherethe charging and detectingrelectrodes are verv-closei'tofrether. Q 'Infsuch cases, as indicated in iiiguretpthe 4electrical impulses 'from the oletecting qelectrodes I .Iand :3.3 can .be supplied :to the :vertical .deiiection :.zplates fm of an oscilloscope il! "where .the horizontales-weep -frequency .off ithecescilloscone is fmade'sto correspond to, and vis'fidcritical to,:that ofztheftirner 42. Thetime interval between-.charging and detecting impulses.

can yfdetermined `directh/"frorn Athe horizontal :dispi-acernent L'be'tween tthe :pulses on f the loscilloscope. .Iflit isdesiredgrthe particularinstrument c-anfbe feocalihratedforrgiven size pipe such that :thefiow'rate is;deiermined directly: from the horilrental ldisplacementof a'the pulses fon. the oscilloscope tube.

While the foregoing description of this invention is based upon the use of a periodic charging of the fluid to form a series of charged increments in the owing stream, each being detected before the formation of the next, it is apparent that a single charging step can be employed if desired. The lapsed time interval between the single charging and its detection can be used to determine a single value for the flow rate. The multiple charging is important in such cases where the timing is eiected by means of an oscilloscope or where the flow rate is changing and it is desired to measure such changes.

While the foregoing description of this invention. relates to the determination by an instrument at a particular fixed level, it is apparent that the now measurements can be made with the instrument being raised or lowered in the bore hole at a constant rate. In such cases a correction for the relative motion of the instrument with respect to the strata is made on the measured iiuid velocity or 110W rate.

It is apparent that inanv modiiications of this invention may be made by those skilled in the art without derartingv from the spirit and scope of the following claims.

I claim:

1. .An apparatus for the determination of liquid flow of a substantially non-ionizable liquid which apparatus comprises a pair of charging electrodes insulated from direct electrical contact with said licuid now, generating means for generating a high voltage direct current, electrical conducting means for momentarily connecting said generating means with said pair of charging electrodes, a pair of detecting electrodes located downstreamwardly from said pair of charging electrodes, means for maintaining said pair of detecting electrodes downstreamwardly in xed spatial relationship to said pair of charging electrodes, a continuous liquid passageway connecting said pair of charging electrodes with said pair of detecting electrodes and time interval measuring means electrically connected with said charging electrodes and said detecting electrodes for determining the lapsed time interval between the charging of said pair of 'charging electrodes and the detecting by said pair of detecting electrodes.

2. An apparatus for measuring liquid ow within a Well bore which comprises a housing having a liquid passageway running therethrough, a pair of insulated charging electrodes mounted in said liquid passageway and insulated from direct electrical contact with said liquid passing therethrough, a pair of insulated detecting electrodes mounted in said liquid passageway which are insulated to prevent direct electrical contact with said liquid passing therethrough, said insulated detecting electrodes being mounted a fixed distance above said insulated charging electrodes, electrical current producing means for producing a high voltage direct current, means for momentarily connecting said electrical current producing means to said pair of charging electrodes for electrostatically charging a portion of said liquid flowing between said charging electrodes, means for supporting said housing Within said Well bore at different levels, and a time interval measuring means electrically connected with said charging electrodes and said detecting electrodes for determining the lapsed time interval between said momentary charging and the subsequent detecting of the residual electrostatic charge on arrival between said pair of detecting electrodes.

3. An apparatus for determining the flow rate of a substantially non-onizable liquid which apparatus comprises a now-conducting means for flowing said liquid from a first location to a second location downstreamwardly a xed distance from said first location, a pair of charging electrodes xed at said Iirstlocation and insulated from direct electrical contact with said liquid flow, means for periodically supplying an electrical current to said charging electrodes for periodically establishing an electric field in an increment of said owing liquid, a pair of detecting electrodes fixed at said second location, said charging electrodes and said detecting electrodes being normally submerged in said liquid, electrostatic eld-detecting means connected across said detecting electrodes, and means electrically connecting said charging electrodes and said electrostatic eld-detecting means for temporally correlating said periodic establishing of an electric eld in said liquid increment with the detection thereof at said detecting electrodes.

EARLE R. ATKINS, JR.

Number Name Date 1,411,796 Meyer Apr. 4, 1922 1,440,778 Foster Jan. 2, 1923 1,611,502 Allen Dec. 21, 1926 1,616,481 Allen Feb. 8, 1927 1,808,709 Blake June 2, 1931 2,333,164 Fisher Nov. 2, 1943 2,353,382 Barrett July 11, 1944 2,453,456 Piety Nov. 9, 1948 FOREIGN PATENTS Number Country Date 615,769 Great Britain Jan. 11, 1949 

